Special Edition Using Linux®, Sixth Edition

Permissions

There are three levels of permissions to files and directories in Linux. These levels correspond to the following three categories :

• User (the owner)

• Group

• Other

Each level, or category, has associated privileges. These privileges come in the form of three permissions: read permissions, write permissions, and execute permissions.

All three levels—Owner, Group, and Other—have read, write, and execute permissions.

In order for the set of permissions for the owner and group to work, the file must have an indicator as to who is the owner and to which group the file belongs. Each file or directory has an owner property (sometimes referred to as the user property) and a group property. The owner, or user, property is set to the ...